We have recently derived a novel algorithm for discriminating action potentials of different neurons from the composite signals obtained with multi-unit nerve recordings using linear electrode arrays. This algorithm is based on phased array processing, and is particularly effective at discriminating superimposed spikes. To our knowledge, this approach has never before been applied to the neural spike discrimination problem. The goals of this project are a) to test, refine and enhance the resolution of this approach, b) to develop an effective, principled approach through which a basic or clinical researcher could select or design an electrode array architecture optimized for the implementation of these new spike discrimination techniques for any specific purpose, and c) to extend the robustness of this algorithm by adding adaptive capabilities. The algorithms will be developed to be compatible with real-time implementation on specialized hardware, as well as for implementation on standard computational hardware. The unified design approach we will develop, which integrates the algorithm with the electrode architecture, will enable construction of systems that will exceed the speed, accuracy and reliability of existing spike sorting algorithms, and provide a robust solution to the spike superposition problem. The attainment of these objectives will have significant impact on both basic and clinical research. The development of accurate and reliable spike sorting techniques will greatly expand researchers' ability to measure and characterize the activity of neuronal populations engaged in neural processing tasks. Advancements in the field of neural prosthetics offer hope that lost sensory, motor and even cognitive functions may ultimately be recoverable, to some significant extent, through the use of neural interface devices that depend on the accurate decoding of neuronal activity patterns. A robust solution to the spike superposition problem, and development of electrode designs with which to implement the algorithms for spike discrimination and neural decoding, will be essential for this area of clinical research. [unreadable] [unreadable]